Comparative Pharmacology
Head-to-head clinical analysis: PROGESTERONE VAGINAL versus PROMETRIUM.
Peer-Reviewed Evidence
Head-to-head clinical analysis: PROGESTERONE VAGINAL versus PROMETRIUM.
Progesterone (Vaginal) vs PROMETRIUM
Comparing the clinical profiles, pharmacokinetic behaviors, and safety indices of these two therapeutic agents.
Progesterone binds to progesterone receptors in the reproductive tract, converting proliferative endometrium to secretory endometrium, and reduces gonadotropin secretion, inhibiting ovulation.
Progesterone binds to progesterone receptors in target tissues, promoting endometrial maturation, reducing uterine contractility, and suppressing ovulation.
For progesterone deficiency (e.g., assisted reproductive technology, luteal phase support): 90 mg intravaginally once daily. For secondary amenorrhea: 45 mg intravaginally every other day for up to 12 doses, then 90 mg if needed. For threatened abortion: 200-400 mg intravaginally once or twice daily.
Oral: 200 mg once daily at bedtime for 12 consecutive days per 28-day cycle in combination with conjugated estrogens 0.625 mg daily. For secondary amenorrhea: 400 mg once daily at bedtime for 10 days. Intravaginal: 4% gel (90 mg) or 8% gel (180 mg) applied every other day for 6 doses in postmenopausal women with intact uterus on estrogen therapy.
None Documented
None Documented
The terminal elimination half-life of progesterone administered vaginally is approximately 5.5 to 6 hours (range: 4.5–8.0 hours) in women with normal renal and hepatic function. This short half-life necessitates twice-daily dosing for sustained effects.
Terminal half-life: Approximately 16-18 hours for oral micronized progesterone (Prometrium); permits twice-daily dosing for luteal phase support.
Primarily hepatic metabolism; about 50-60% of metabolites are excreted renally as glucuronide conjugates, with approximately 30-40% eliminated via feces. Less than 1% of unchanged progesterone is excreted in urine.
Urine (50-60% as metabolites, <1% unchanged); feces (20-30% as metabolites); minor biliary elimination.
Category A/B
Category C
Progestin
Progestin